Ore-briqueting.



posure to the gases of the furnace to which I'o itawtng. Applicationfiled August 14, 1908. Serial No. 448,544.

I To all whom it may concern: t

' slag whichhas osghiti.

Patent No. 78fifpi'3'is best suited STATES PATENT OFFICE,

Be it known that I, Wxmuulu Lrssiso, a

' rsu ject of the German Emperor, residing at Troisdorf. ltheinland,Germany, have inventedeertain new and useful 1m n'ovementsinGre-Briquetiug, of which the ollowing is a s dedication,

' he UlJjtttt of th s invention Is to produce to pieces or ermrihle intransport to or exthe ore is to be smelted.

According tothepresent invention the pulverized charge, oredustrorfine-' rained ore is eaked wit the presence of u 51th 'or withoutadmixtures. 'l'ests hmeshown, that slag treated ,as set forthin tluis'ieeifieation of my U. S. for t to purpose indimlted. j- Ilowever, thepulverization of the slug may also he performed by the direct action ofa stream-of air charged-with pulverized admixtures,for'exzun 'ile lune.

.For the manufacture of ore-liu-iquets for smeltin r purposes :it hasheeu' proposed mix pu verized iron oreund the like with roundblast-furnace slag, alumina and hue. The term cement cannot beaccuretely applied tovthe niass'forlued by these i admixtun-s. thoughthe'said mass unghtghtarded' as the 'rau material of cement,

without the binding power imparted by burning. In practice it has beenfound that briquets made of the mixture deserilmd, or of similarmixtures, *do not even possess soilicient durability to enable them toconveyed to the v ast furnace or even if they can be placed whole in theh eruted in the upper part of the furnace cause the cakes to,crumble todust, which is blown .out of the furnace by the blast before it reachesthe "smelting zone, so that the iron this processthe bindingBpcctflcetton of Letters Patent. Patented hlarzz, 19

briquets 'of ore a nd slagewhich will not fall 1 ,the-aid of blasturna eously been treated in of -bind1n agent lcqltlletl renders not only lastfuruaee the l hot air-blast and the vapors and gases gen- WILHELMLE$SING OF TROISDORFJGERMANY. 4

OBE-BRIQU ETING.

; state to the action of high pressure steam, it hasheen found that theminute cavities in the binding agent contain water which is evaporatedwhen the briquets enter the u perzone of the smelting furnace, and t esteam thus generated causes the hriquets to crumble before they reachthe smelting zone of the furnaoe.

'.,In my present invention the binding agent is perfeetlydrfy, andproduces highly porous brl uetspwhic 1 ar ver ermeable to gases, sotatthe reduction of tlie ore is materiallv assisted by the actionofcarbon monoxh. The improved briquets do not require it high degree ofcompression, such as would reduce their porosity, and the smallerproportion the :ananu ucture of the briquets', but also obviates therisk of loss of ore due to the em- I bedding of ore-particles in avitreous muss ;by which access of the re'dmring guses is prevented.

The pulverized sla ris, according to the present invention, fine yground, either alone or with admixtures adapted to increase its bindingpower in. ease the said binding power is not naturally of :1 hi h orderor has not. previously been increase by means of admixtures introdtu-cddurin r the-pulveriz- 'iug process. The meuly pow or obtained by withthe ore, iron residue, ore-dust or the like and the mixture isluoldedunder pressure in the usual uunner. The cakw thus produeed becomein -a con iparatively short time sullieientlyhard to hrs-transported andsubjected to the smelting process. This is; due to the fact that durin rthe pulverization of molten blast furnaoe slag the greut'er part of thesuljur eontainedtherein is' separated in counteracts the inding power ofthe cement. If admixtures are introduced during the pulverizing prmessthe pulverization is accompaiuied by a process anulo ous to that whichtakes place in a. cement urnace, and this process is considerablyassisted by the burning of the sulfur und sulfui-eted hydrogen, so thatthe product is at least equiviilent, in bindin and cement the importantadvantages'that; it led uees the cos of nanufacturm the ore t thesmeltingprooess, more economical, and

the grinding process is intimately mixed.

cakes, thetsmeller quentitiestliereo m suf the form of stflfur dioxid orsulfureted hydroge-n, or bothLso that the sulfur no'longer power, tolorthind cement of {good quality. It has, however, over Portficient,that the cakes produced are more porous or ermeable to the furnace ses,and that e chemical composition 0 the binding agent is better adaptedfor the purpose in view. a

It has been found that the binding. agent is considerably improved byadding a suitable quantity of alkaline salt, which may either be groundup with the slag or added after the grinding. 13% means of suchaddition' the setting of t e briquets is accelerated, and risk ofcracking by frost is reduced, more articularly if the salt used is"chlorid of ca cium'. On the other hand the presence of salts of thealkaline metals or earth metals prevents too rapid drying of thebriquets, es ecially in summer, and ,enables aftificlal heat to beapplied without risk of drying the mass before the bri nets have set.Chlorid of calcium and ch orid of potassium also have the advantage thatthey assist in the elimination bf sulfur, phosphorus, copper, zinc,arsenic and the like during the smelting with the silica in the s ag andthe iron oxid in the, ore they cause, moreover, a fusing together of thebriquet-particles and thus prevent sudden disintegration of the briuetsby the heat of the smelting zone.

nether advantage of the alkaline salts is that thev render the slagbasic and easily liquefiable, so that the proportion oflime canincreased without risk of producing a tough, viscous mass dangerous tothe furnace. The alkalies also assist in the extraction of the manganesewith the iron, which is an important advanta e.

A very important a vantage of using,

for the manufacture of the ore briquets, slag which has been granulatedin the presence of air, lies in the fact that the air-treatment of theslag renders it possible to use slags which are unsuitable for thebriqueting rocesses hitherto used, by reason of the Purge roportion ofmanganese therein. Tests have been made with spiegel-eisen slag conasmuch as 10% of manganese taining nearly free from phosphorus, with ahigh I rocess; by coaction v proportion of lime,.and it was found thatby granulation this slag is converted e (1 into a ginding agentparticularly suitable for brique'ting, by reason of the large proportionof manganese. The manganese not only enriches t is iron but also'assistsin eliminating sulfur. This latter function is important if the bindingagent is used in conjunction with spent pyrites nearly free fromphosphorus but containing a considerable proportion of sulfur. If thepresence of manganese inthe iron is not desired, a considerableproportion of man nese in the binding a ent is still usefu for renderinthe slag asic and easily liquefiable aim for binding the sulfurpresent.

lVhat I claim as my invention and desire to secure by Letters Patent ofthe United States is y i 1. In ore briqueting the process ,ofvproducingslag cement which consists in granulating blast furnace slag in thepresence of air, grinding the product in the resence of materialsadapted to strengtgen the u-mentitious properties mixing the productwith ore and forming same into briquets.

2. In orebriqueting, the process of pro 3. In ore briqueting the processof producing slag cement which consists in granulating blast furnaceslag in the presence of air, 'rindin the roduct in the presence ofalkaline sa ts .a apted to strengthen the cementitious properties mixingthe product with ore andforming same into briquets.

In witness whereof I have signed thisspecificationin the presence of twowitnesses.

WILHELM LESSING. \Vitnesses: r

LOUIS VANDORN,

H. Srnnznn.

